In the past, a number of devices have been devised to address the problem of safety in connection with electrical receptacles. One problem that has been addressed is the problem of infants and small children making contact with metal electrical conduits within a receptacle by insertion of either their fingers or metal objects into the holes in such receptacles that are needed to receive the male prongs of a plug. Without some method of inhibiting such contact, an infant or small child can suffer serious injury.
One method that has been addressed in the past is to provide a non-conducting plug having non-conducting prong members inserted into receptacle. Such devices are often difficult for a less dextrous infant or child to pull out, but can be readily removed by an adult with a little effort. In either case, that is, either the infant or the adult, it is possible to remove this blocking plug and still expose the person to danger. One of the problems with this method is the fact that not only is the blocking non-conducting plug removable, but is easily removable by an adult and does not prevent an adult from being shocked when inserting a male plug into the receptacle. This problem is aggravtated when there is no ground circuit which often occurs during the active insertion because the ground circuit is not complete until insertion is complete, or there may be no provision for a ground blade in the plug being inserted.
A number of other devices have been addressed in the past to the problem of insuring that there are electrical conduit members for grounding a circuit. These devices often provide a spring or springs, linkages, and sometimes even solenoids and relays to achieve this objective.
One of the problems of these devices is that they do not insure that there will be no electricity flowing into a device when there is no ground prong on the plug of such a device.
Accordingly, it is an object of this invention to prevent electrical conduction unless there is a male grounding prong on the plug of the electrical device to be inserted into a receptacle.
It is a further object of this invention to provide a means of blocking, by an electrically non-conductive member, the apertures in an electrical receptacle responsive to removal of a male plug therefrom.
It is another object of this invention to open an otherwise blocked aperture in the electrical outlet responsive to insertion of an electrical male plug thereinto.
It is another object of this invention to provide means preventing even accidental contact with electrically active metal conducting members of an electrical receptacle with any external objects while allowing the unblocking of same only upon insertion by a prong of a male plug into the ground plug receptacle thereof.
It is another object of this invention to provide a safety electrical receptacle that insures that no electrical contact is made unless the male plug being inserted thereinto has a prong as part of a ground circuit.
These and other objects of this invention are achieved by the provision of a member having electrically non-conductive components blocking the aperture for access to electrical conducting members within a receptacle; said member operable to move mechanically responsive to engagement in a camming action with the ground prong of a male plug. The movement generated by this camming action moves the non-conductive component out of a blocking position with respect to the aperture so that the prongs of the plug operable to carry the energy to the device to be energized can pass into the aperture and come into mechanical and electrical contact with the electrically conductive components of the receptacle.
The above provides structures that are tamperproof, dustproof, dusttight, raintight, and weatherproof as defined by Article 100 of the "National Electrical Code 1984", as published by National Fire Protection Association, Battermarch Park, Quincy, Mass. The above apparatus also provides a dead front receptacle as defined by Section 70-8 of the "National Electrical Code". By "dead front" is meant in this context, without electrically live parts exposed to a person on the operating side of the equipment.
Also provided by this apparatus is a dustproof receptacle as defined by Section 70-8 of the "National Electrical Code". Specifically, "dustproof" means, in this context, so constructed or protected that dust will not interfere with its successful operation. Also provided by this apparatus is a dusttight receptacle as defined by Section 70-8 of the "National Electrical Code". "Dusttight" means, in this context, so constructed that dust will not enter the enclosing case under specified test conditions.
Also provided by this apparatus is an unexposed receptacle where the term "exposed" is that used in Section 70-9 of Article 100 of the "National Electrical Code". Specifically, in this context, "exposed" means, as applied to live parts, capable of being inadvertently touched or approached nearer than a safe distance by a person. It is applied to parts not suitably guarded, isolated, or insulated.
What is provided is an apparatus for a damp location that is rainproof and raintight, where the terms damp location, rainproof, and raintight are that provided by the definitions in Article 100 of the "National Electrical Code". Specifically, a receptacle shall be considered to be in a damp location in partially protected locations under roofed open porches, canopies, marquees, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses. In this context, "rainproof" means so constructed, protected, or treated as to prevent rain from interfering with the successful operation of the apparatus under specified test conditions. In this context, "raintight" means so constructed or protected that exposure to a beating rain will not result in the entrance of water under specified test conditions.
This apparatus also provides a weatherproof receptacle as defined in Section 70-16 of Article 100 of the "National Electrical Code". In this context, "weatherproof" means so constructed or protected that exposure to the weather will not interfere with successful operation. Rainproof, raintight, or watertight equipment can fulfill the requirements for weatherproof where varying weather conditions other than wetness, such as snow, ice, dust, or temperature extremes, are not a factor.
Also provided is a grounding type receptacle or receptacle to be grounded where the definitions of "grounding type" and "to be grounded" are those found in Article 210 of the "National Electrical Code".